Q$\mathrm{.}4($b$)$ Figure Q$\mathrm{.}4($b$)$ below represents the flow beneath a sheet piling wall. If the coefficient of permeability $(k)$ is $1\mathrm{.}2{10}^{-4}\frac{m}{s},$ void ratio $($e$)$ is $1\mathrm{.}2,$ specific gravity $(G_s)$ of soil is $2\mathrm{.}65$ and specific weight of water is $9\mathrm{.}81k\frac{N}{m^3}.$

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Determine the following:

$($i$)$ total head at CD;

$($ii$)$ pore water pressure at Point $P$;

$($iii$)$ pore water pressure at Point $x$;

$($iv$)$ the flow per meter width underneath the sheet pile after $1$ hour;

$($v$)$ critical hydraulic gradient $(i_c)$;

$($vi$)$ the maximum exit hydraulic gradient at Point $E($given that the length of the exit division is $0\mathrm{.}6m$ long$)$; and

$($vii$)$ the factor of safety against piping.